Opening/Closing Device and Mobile Device Using the Same

ABSTRACT

It is an object of the present invention to provide an opening/closing device which can be produced simple in construction and reduce the surface pressure of its cam portions, and a mobile phone which can be reduced in cost and sufficiently reliable in the hinged members by using the opening/closing device. In the opening/closing device operable to rotate the second member ( 30 ) with respect to the first member ( 20 ) hingedly connected the second member ( 30 ) in an opening operation direction by operating first and second rotation cams ( 160, 140 ), and a movable cam ( 150 ) held in engagement with the second rotation cam ( 140 ) in response to the displacement of the operation cam ( 130 ), the second rotation cam ( 140 ) and the movable cam ( 150 ) have a plurality of kinds of end cam portions (( 142, 153 ), ( 143, 154 )) formed thereon at different radiuses (r 1,  r 2 ) from the guide center axis ( 110   c ) in opposing relationship with each other, the urging direction of the urging means ( 170 ) to the second member ( 30 ) is changed by the end cam portions (( 142, 153 ), ( 143, 154 )) when the operation cam ( 130 ) is operated to cause the first rotation cam ( 160 ) to be rotated from the predetermined operation starting position.

TECHNICAL FIELD

The present invention relates to an opening/closing device and a mobiledevice using the same, and in particular to an opening/closing deviceprovided with a function to have a foldable type of hinge connectionbody having one and the other members hinged together operated into anopened state with a simple pushing operation of a pushing button.

BACKGROUND OF TECHNOLOGY

As one of conventional mobile devices represented by mobile phones, PDA(Personal Digital Assistance) and the like, those mobile devices havinga housing of a foldable type small in size, light in weight andexcellent in protective function are widely used. The mobile device ofthis kind is difficult to manipulate the opening operation of thehousing forming part of the mobile device as the housing becomes smallin size. In the recent years, there has been proposed a mobile devicewhich is excellent in the manipulation of the opening operation of thehousing by providing the mobile device with an opening/closing device toensure that the opening/closing operation of the mobile device iscarried out simply by the pushing operation of the push button providedin the one hinged member of the housing of the mobile device.

As the opening/closing device of this kind, there has been widely knowna mobile device (for example see following patent document 1) whichcomprises a plurality of rotation cams including a conversion cam forconverting the pushing operation to the rotation motion when the pushingbutton is pushed, a release cam driven by the conversion cam and areturning spring, a fixed cam and a reversing cam to be operated by therelease cam, the above cams being provided in a cylindrical guide memberfixed to one hinged member to be hinged with the other hinged member. Inresponse to the pushing operation of the pushing button, the engagingstate between the rotation cam and the movable cam fixed to the housingand thus moved together with the housing is changed to make it possiblefor the opening/closing device to be opened and closed by using theurging force of the spring.

Patent document 1: Patent laying open publication 2003-232336

DISCLOSURE OF THE INVENTION Problem to be solved by the Invention

Many problems are encountered in that the conventional opening/closingdevice is complex in structure, difficult in making the device small insize, and expensive in production cost by reason that the conventionalopening/closing device is constituted by many kinds of rotation camssuch as a fixed cam for maintaining and fixing the housing in a closedstate, a releasing cam for releasing the fixed cam, a reversing cam usedin place of the releasing cam to be engaged with the movable cam to makethe movable cam and the movable side housing to be rotated in theopening operation direction, and the like.

The fact that the rotation cams of the conventional mobile devicerespectively have small cam portions provided in the narrow space in thehinged members of the mobile device results in the fact that each of thesmall cam portions is obliged to have a high face pressure and canendure only a certain level of pressure, thereby making it unavoidableto produce each of the rotation cams with a material excellent inmoldability and so far difficult in doing so. Also in this aspect, theprior-art mobile device became costly.

This means that the conventional mobile device found it difficult notonly to make the mobile device small in size but also to produce themobile device at a reduced cost.

It is, therefore, an object of the present invention to provide anopening/closing device which can be produced simple in construction andinexpensive in production by reducing the number of the parts formingpart of the mobile device and to provide a mobile device small in size,reduced in cost and sufficiently reliable in the hinged members.

Means for Solving the Problem

In order to attain the above object, the opening/closing deviceaccording to the present invention comprises (1) a fixed guide memberfixed to a first member to be hingedly connected and having a guidecenter axis extending along a center axis of a hinge connection; anoperation cam supported on the fixed guide member to be displaceablewith respect to the fixed guide member in a predetermined operationdirection by an external operation force; a first rotation cam rotatablysupported on the fixed guide member to be engaged with the operation camand to be rotated with respect to the fixed guide member around theguide center axis in response to the displacement of the operation cam;a second rotation cam supported on the fixed guide member to bedisplaceable along and rotatable around the guide cent axis in responseto the rotation of the first rotation cam; a movable cam regulated frombeing rotated around the guide center axis with respect to a secondmember hingedly connected with the first member, and positioned inface-to-face relationship with the second rotation cam and displaceablewith respect to the fixed guide member along the guide center axis androtatable around the guide center axis; urging means for urging themovable cam toward the second rotation cam in one of an openingoperation direction to have the second member moved away from the firstmember and a closing operation direction to have the second member movedtoward the first member in response to the engagement state of thesecond rotation cam and the movable cam, and returning means forreturning the first rotation cam to a predetermined operation startingposition of the operation cam and for returning the second rotation camto a predetermined operation starting position where the second memberis urged toward the closing operation direction by the urging means, thesecond member being rotated with respect to the first member toward theopening operation direction through the movable cam by the urging forceof the urging means when the operation cam is displaced in thepredetermined operation direction by the external operation force,wherein the second rotation cam and the movable cam respectively have aplurality of kinds of end cam portions formed thereon at differentradiuses from the guide center axis in opposing relationship with eachother, the plurality of kinds of end cam portions including urgingdirection changing outer cam portions changed in engagement state whilebeing axially pressed by the urging means to allow the urging directionof the second member to be changed when the operation cam is operated tocause the first rotation cam to be rotated from the predeterminedoperation starting position, and urging direction changing inner camportions engaged with each other at respective positions closer to theguide center axis than the urging direction changing outer cam portionsand changed in engagement state in synchronism with the urging directionchanging outer cam portions while being axially pressed by the urgingmeans to allow the urging direction of the second member to be changedwhen the operation cam is operated to cause the first rotation cam to berotated from the predetermined operation starting position.

In this embodiment, the fixed cam and the second rotation cam arerespectively provided with the urging direction changing outer camportions and the urging direction changing inner cam portions differentin engagement radius, the engaging states of the engaging portions ofthe fixed cam and the second rotation cam are changed in synchronismwith each other and the urging direction of the compression spring isalso changed, so that the individual urging direction changing camportions can be provided with sufficient operation spaces, and theengaging cams can sufficiently secure minimum engagement angle rangeseven with a plural kinds of the urging direction changing cam portionsprovided in the opening/closing device. This makes it possible to lowerthe surface pressure of the engaged cam portions, thereby realizing tomold the fixed cam and the second rotation cam with, for example,materials excellent in moldability, thereby making it possible to setthe operation range of the individual urging direction changing camportion at more than 180 degrees and to sufficiently secure theengagement range of cams opposite to each other. The opening/closingdevice according to the present invention can switch urging directionsof the compression spring without further comprising a cam for switchingurging directions of the compression spring, and can be small in sizeand weight, improved in production cost, and improved in durability witha reduced engaging force. Flexible location in a rotation direction andin an axis direction of the urging direction changing outer cam portionswith an engaging operation of the urging direction changing inner camportions greatly expands the possibility of the opening/closing device.

In the opening/closing device according to the present invention, it ispreferable that (2) the urging direction changing outer cam portion andthe urging direction changing inner cam portion of the second rotationcam are positioned in opposing relationship with each other across therotation center axis of the second rotation cam and 180 degrees spacedapart from each other in the rotation direction of the second rotationcam. The opening/closing device thus constructed can prevent eachrotation cam from produce a moment having the guide center lineinclined, the operation angle range of the cam portions different inengagement radius from each other is larger than the operation anglerange of the cam portions the same in engagement radius as each other.

In the opening/closing device according to the present invention, it ispreferable that (3) the urging direction changing outer cam portion andthe urging direction changing inner cam portion of the second rotationcam respectively have first inclined cam surfaces inclined inpredetermined directions with respect to a surface perpendicular to theguide center axis to urge the movable cam toward the closing operationdirection of the second member when the second member is positioned inthe neighborhood of the closing operation position closest with thefirst member in the state of the second rotation cam returned to thepredetermined operation starting position, and second inclined camsurfaces inclined with respect to the surface perpendicular to the guidecenter axis, and top portions projected toward the movable cam betweenthe first inclined cam surfaces and the second inclined cam surfaces toallow the urging direction of the second member to be changed by theurging means.

In this construction, each of the urging direction changing cam portionscan be easily produced by a molder or the like to be opened and closedin a direction of its rotation axis.

In the opening/closing device according to the present invention, it ispreferable that (4) the fixed guide member has guide shaft portions incoaxial relationship thereof, the first rotation cam and the secondrotation cam being guided by the guide shaft portion in coaxialrelationship with the fixed guide member. The guide shaft portion canstabilize the rotation center of the first and second rotation cams toensure that each rotation cam is kept in good working condition. Theopening/closing device can be simply assembled. A center portion of eachrotation cam is effectively used as a guide portion by reason that eachof the urging direction changing cam portions is spaced from the guidecenter axis.

It is preferable that (5) the opening/closing device according to thepresent invention further comprise a bottomed cylindrical body supportedon and coaxial with the guide shaft portion and integrally engaged inrotation direction with the movable cam and the second member, theurging means being constituted by a resilient member positioned betweenthe bottomed cylindrical body and the movable cam. This construction cancause the bottomed cylindrical body to be supported on the guide shaftportion and can accommodate the resilient member as urging means in thebottomed cylindrical body. This makes it possible to handle theessential elements forming part of the opening/closing device as a uniton the guide shaft portion. Also, this makes it possible to have thebottomed cylindrical body function to guide the movable cam while themovable cam is axially displaced and to engage with and thus integrallyrotate together with other members other than the function to hold oneend of the resilient member.

In the opening/closing device according to the present invention, it ispreferable that (6) the fixed guide member and the movable cam haverespective end surface positioning cam portions axially opposing witheach other, the movable cam being disengaged from the second rotationcam to have the end surface positioning cam portions of the fixed guidemember and the movable cam engaged with each other and to have thesecond member positioned and retained at the opening position when thesecond member is moved to the opening position where the second memberis remotest from the first member. It is possible to attain a smoothtransferring operation between the engagement and disengagementoperations of the second rotation cam and the movable cam and thepositioning operations of the end surface positioning cam portions.

In the opening/closing device according to the present invention, it ispreferable that (7) the end surface positioning cam portions of thefixed guide member are engaged with and disengaged from each other at aradius position closer to the guide center axis than the kinds of endcam portions. In this construction, the end surface positioning camportions of the fixed guide member and the movable cam can be engagedwith each other through the center portion of the second rotation cam.The fixed guide member may have a guide shaft portion. In this case, theend surface positioning cam portion of the fixed guide member can bearranged at an appropriate position of the guide shaft portion. The endsurface positioning cam portions arranged at an appropriate position ofthe guide shaft portion make it possible to have the end surfacepositioning cam portions reliably engaged with the fixed cam.

In the opening/closing device according to the present invention, (8)the second inclined cam surface of the urging direction changing outercam portion and the urging direction changing inner cam portion of thesecond rotation cam has side portions inclined at different grades withrespect to the surface perpendicular to the guide center axis and anintermediate portion intervening between the side portions, theintermediate portion and the side portions may rotate the second memberat a reduced speed when the second member is rotated with respect to thefirst member in the opening operation direction. The movable housing isrotated with respect to the fixed housing in response to an urging forceof the urging means by reason that, when the movable housing is rotatedin an opening operation direction with respect to the fixed housing inresponse to an urging force of the compression spring, theopening/closing hinge unit can allow the movable housing to be rotatedat a reduced speed. The present invention can attain various openingoperations of the mobile device.

In the opening/closing device according to the present invention, (9)the second inclined cam surface of the urging direction changing outercam portion and the urging direction changing inner cam portion of thesecond rotation cam has side portions and an intermediate portionintervening between the side portions, and being inclined oppositely toand the side portions each other at different grades with respect to thesurface perpendicular to the guide center axis to allow the intermediateportions of the second inclined cam surfaces to stop the second memberwhen the second member is rotated by the urging force of the urgingmeans with respect to the first member in the opening operationdirection. In this construction, when the movable housing is rotated inan opening operation direction with respect to the fixed housing inresponse to an urging force of the compression spring, theopening/closing hinge unit can allow the movable housing to be rotatedat a reduced speed.

A mobile device using (10) the opening/closing device as set forth inclaim 1, the first member and the second member hingedly connected witheach other collectively constitute an openable and closable housing of afoldable type. In this construction, the mobile device using theopening/closing device excellent in durability and reliability can besmall in size, light in weight, and at relatively low cost excellent indurability and reliability. In this construction, when the movablehousing is rotated in an opening operation direction with respect to thefixed housing in response to an urging force of the compression spring,the opening/closing hinge unit can stop rotating the movable housing atan intermediate portion of the inclined cam surface on the basis of thefunction of the mobile device provided with the opening/closing device.

The present invention can provide an opening/closing device small insize, light in weight and suitable as a mobile device by the reason thatthe rotation of the first rotation cam with the operation of theoperation cam causes the second rotation cam guided by the inclinedguide portion to be rotated while axially moving under the pressingforce of the movable cam and thus to be changed in the engagement statewith the movable cam, thereby making the urging direction of the secondmember changed with the urging means so that there is no need for othercams which cause the urging direction of the urging means to be changed,resulting in reducing the number of parts and elements to be assembledin the opening/closing device. As a consequence, the present inventioncan provide a mobile device which is small in size, produced at lowcost, and sufficiently reliable in the hinge connection thereof by usingthe opening/closing device which can reduce the surface pressuresapplied on the rotation cams, thereby making the opening/closing devisesimple in construction, small in size and produced at low cost.

BRIEF DESCRIPTION OF THE DRAWINGS

The characteristics and advantageous aspects of the present inventionwill be better understood from the following detailed description whenconsidered in connection with attached drawings, wherein:

FIG. 1 shows a mobile phone provided with an opening/closing deviceaccording to a first embodiment of the present invention, (a) is aperspective view showing a closed state in which the opening/closingdevice is, and (b) is a perspective view showing an opened state inwhich the opening/closing device is;

FIG. 2 is a cross sectional view of a hinged connection portion formingpart of the mobile phone shown in FIG. 1;

FIG. 3 is a perspective explosion view of the opening/closing deviceaccording to the first embodiment of the present invention;

FIG. 4 is a front view of essential parts illustrating the internalconstruction of the opening/closing device according to the firstembodiment of the present invention;

FIG. 5 shows a push cam forming part of the opening/closing deviceaccording to the first embodiment of the present invention, (a) is itsfront view, (b) is a view seen from the arrow B in the front view ofFIG. 5( a), and (c) is a view seen from the arrow C in the view (b) ofFIG. 5( a);

FIG. 6 shows a fixed case forming part of the opening/closing deviceaccording to the first embodiment of the present invention, (a) is itsfront view, (b) is its under view, and its cross sectional front view;

FIG. 7 is a view showing both axial end faces of the fixed case shown inFIG. 6, (a) is an end face view seen from the inside of theopening/closing device, and (b) is an end view seen from the outside ofthe opening/closing device;

FIG. 8 shows a lock release cam forming part of the opening/closingdevice according to the first embodiment of the present invention, (a)is its front view, (b) is a view seen from the arrow B in the front view(a) of FIG. 8, and (c) is a view seen from the arrow C in the view (b)of FIG. 8;

FIG. 9 shows a fixed cam forming part of the opening/closing deviceaccording to the first embodiment of the present invention, (a) is itsfront view, (b) is a view seen from the arrow B in the front view (a) ofFIG. 9, and (c) is a view seen from the arrow C in the view (b) of FIG.9;

FIG. 10 shows a plurality of cam shapes of fixed cams shown in FIG. 9,(a) is a cross sectional view taken along the lines A-A in FIG. 9( c),and (b) is a cross sectional view taken along the lines B-B in FIG. 9(c);

FIG. 11 shows a rotation cam forming part of the opening/closing deviceaccording to the first embodiment of the present invention, (a) is itsfront view seen from the parallel cut face for stopping rotation of therotation cam, (b) is a view seen from the arrow B in FIG. 11( a), and(c) is a view seen from the arrow C in FIG. 11( a);

FIG. 12 is schematic motion explanation views showing a relativedisplacement of an essential cam only when the housing forming part ofthe mobile phone according to the first embodiment of the presentinvention is manually opened;

FIG. 13 is schematic motion explanation views showing a relativedisplacement of an essential cam only when the housing forming part ofthe mobile phone according to the first embodiment of the presentinvention is opened by the push button;

FIG. 14 is a motion explanation view showing relative displacements ofessential cams in phantom lines in the initial operation of the pushbutton shown in FIG. 13( a), and in solid lines in the released state ofthe fixed cam;

FIG. 15 is a motion explanation view showing relative displacements ofessential cams after the initial operation of the push button shown inFIG. 13( c);

FIG. 16 is a motion explanation view showing relative displacements ofessential cams in part fragmentally cross sectioned and showing thestates of the positioning parts and elements from the stage of the camsengaged with one to others showed in FIG. 13( c) to the stage of thecams positioned in the opened state shown in FIG. 13( d);

FIG. 17 is a motion explanation view schematically showing a fixed camforming part of the opening/closing device according to the secondembodiment of the invention; and

FIG. 18 is a motion explanation view schematically showing a fixed camforming part of the opening/closing device according to the thirdembodiment of the invention.

EXPLANATION OF THE REFERENCE NUMERALS

10: mobile telephone (mobile device)

10 a: center axis of the hinge connection

20: fixed housing (first member)

25: push button (operation member)

30: movable housing (second member)

100: opening/closing hinge unit (opening/closing device)

110: fixed case (fixed guide member)

110 c: guide center axis

116: cam support axial portion (guide axial portion)

116 a, 151 a: end surface positioning cam portion

120: movable case (bottomed cylindrical body)

130: push cam (operation cam)

140, 240, 340: fixed cam (second rotation cam)

142, 242, 342: urging direction changing outer cam portion (end surfacecam portion)

143, 243, 343: urging direction changing inner cam portion (end surfacecam portion)

142 a, 143 a, 242 a, 243 a, 342 a, 343 a: first inclined cam surface(one of the inclined cam surfaces)

142 b, 143 b, 242 b, 243 b, 342 b, 343 b: top portion

142 c, 143 c, 242 c, 243 c, 342 c, 343 c: second inclined cam surface(the other of the inclined cam surfaces, portions between which anintermediate portion intervenes)

142 d, 143 d, 242 d, 243 d, 342 d, 343 d: intermediate speed reductionarea (intermediate portion)

142 e, 143 e, 242 e, 243 e, 342 e, 343 e: elongated inclined surface(the other of the inclined cam surfaces, portions between which anintermediate portion intervenes)

150, 250, 350: rotation cam (movable cam)

153, 253, 353: cam portion (urging direction changing outer cam portion)

154, 254, 354: cam portion (urging direction changing inner cam portion)

153 b, 154 b: top portion

153 c, 154 c: second inclined cam surface

160: lock releasing cam (first rotation cam)

180: guide shaft (guide shaft portion)

The PREFERRED EMBODIMENT OF THE INVENTION

The preferred embodiments of the present invention will hereinafter bedescribed in detail with reference to the attached drawings.

First Embodiment

FIGS. 1-16 show an opening/closing device according to the firstembodiment of the present invention and a mobile phone provided with theopening/closing device.

The mobile phone 10 is shown in FIGS. 1 and 2 to be a mobile type ofinformation terminal (mobile device) and a foldable type to be handledby a single hand, and comprises a pair of housings 20 and 30 hingedlyconnected together and thus relatively rotatable with respect to eachother. The housing 20 has an operation surface 21 provided with aplurality of operation portions 21 a, 21 b, and 21 c, a sound inputportion (not shown) and the like. The operation surface 21 is opened andclosed by the rotation of the housing 30. The housing 30 has a surfaceprovided with a display screen 31 and a sound output portion (with noreference numeral), the surface being in opposing relationship with theoperation surface 21 of the housing 20 when the mobile phone 10 is in afolded state. The housings 20 and 30 respectively have electric circuitsprovided therein for communications, display, sound processing andothers. In usual cases, the housing 20 provided with the operationportions 21 a, 21 b, and 21 c is supported by one hand, so that thehousing 20 is called a fixed housing and the housing 30 is called amovable housing in the embodiments hereinafter appearing.

As shown in FIG. 2, the hingedly connected portion 11 forming part ofthe mobile phone 10 is provided at its one end portion with anopening/closing hinge unit 100 functioned as an opening/closing deviceand at the other end portion formed with wiring passageways 26 and 33.

The opening/closing hinge unit 100 is shown in FIGS. 3 and 4 to comprisea fixed case 110 (fixed guide member) fixed to the fixed housing 20,i.e., a first member of hingedly connected members, a movable case 120made up of a bottomed cylindrical body integrally connected in therotation direction with a hinged portion 32 forming part of the movablehousing 30, i.e., a second member of hinged connected members, to beregulated from being rotated around the axis thereof, a push cam 130supported on the one end portion of the fixed case 110 to be axiallydisplaceable with respect to the fixed case 110, a plurality of rotationcams accommodated in and supported by the fixed case 110 and including afixed cam 140 (second rotation cam) and a lock releasing cam 160 (firstrotation cam), a rotation cam 150 (movable cam) accommodated in andsupported by the movable case 120 in engagement with the fixed cam 140to be axially displaceable with respect to the movable case 120 androtated together with the movable case 120, a compression spring 170(resilient member) disposed between the movable case 120 and therotation cam 150, a guide shaft 180 (guide shaft portion) coaxiallydisposed in and supported by the fixed case 110, and a returning spring190 (return means) for returning the lock releasing cam 160 to thepredetermined operation starting position.

The fixed case 110 has a guide center axis 110 c positioned on thecenter axis 10 a of the hinge connection between the fixed housing 20and the movable housing 30 and fixed to one of hingedly connecting units23 and 24 (not shown in detail) which serve to hingedly connect thefixed housing 20 and the movable housing 30, for example, an innersurface of a fixed housing side portion of the hingedly connecting unit23.

The push cam 130 is disposed in the hingedly connecting unit 23 andaxially inwardly operated from an external force (in a direction shownby an arrow mark 10 b in FIG. 4) by way of a push button 25 provided inthe hingedly connected portion 11 (for example the fixed housing 20).The push cam 130 serves as an operation cam to be displaced in an axialdirection, i.e., an operation direction with respect to the fixed case110 by the external force of the push button 25. The operation camnecessarily may not be a push type of one such as a push cam 130 and maybe of those types, a lever type, a slide type and a rotation type notspecified in the input operation direction if the operation force isimparted along the guide center direction of the fixed case 110.

In the opening/closing hinge unit 100 of the present embodiment, thepush cam 130 is shaped as shown for example in FIG. 5, while the fixedcase 110 is of shape as shown for example in FIGS. 6 and 7.

In FIG. 5, the push cam 130 is formed with a guide shaft receiving hole130 a to receive a guide shaft 180 and disposed on the guide center axis110 c of the fixed case 110 through the guide shaft 180. The push cam130 has an operation end portion 131 having an operation force from thepush button 25 imparted thereon, a rotation stopping portion 133 formedby a pair of parallel flat cut portions adapted to be received in areceiving hole 113 (see FIG. 3) formed in the fixed case 110, and a pairof cam portions 134 designed to rotate a lock releasing cam 160 inengagement with the lock releasing cam 160. The cam portions 134 haverespective inclined portions 134 a each having a shape in conformitywith the shape of each of operation side cam portions 162 forming partof the lock releasing cam 160. The lock releasing cam 160 has a pair ofoperation side cam portions 162 to be respectively engaged with the camportions 134, and is rotatable within the range of a predeterminedrotation angle in response to the axial displacement of the push cam130.

As shown in FIG. 8, the pair of operation side cam portions 162 providedon one end portion of the lock releasing cam 160 respectively haveinclined surfaces 162 a and are disposed in 180 degrees symmetricalrelationship with each other with respect to the center axis 160 c ofthe guide hole 160 a. With respect to the pair of the operation side camportions 162, a pair of fan-shaped holes 110 h (see FIGS. 7( a) and7(b)) are formed in the intermediate inner bottom wall portion 117 ofthe fixed case 110 in 180 degrees symmetrical relationship with eachother with respect to the center axis 160 c of the guide hole 160 a asshown in FIG. 6( c). The lock releasing cam 160 is held in slidableengagement with the intermediate inner bottom wall portion 117 of thefixed case 110 at its seat face 161 formed on the lock releasing cam 160in perpendicular relationship with the center axis 160 c of the guidehole 160 a. The lock releasing cam 160 has a pair of releasing camportions 163 at the other end side thereof, the releasing cam portions163 each having a fixed cam holding surface 163 a and an inclinedsurface 163 b held in engagement with the fixed cam 140. The releasingcam portions 163 are disposed in 180 degrees symmetrical relationshipwith each other with respect to the center axis 160 c of the guide hole160 a.

As shown in FIG. 6( c), the fixed case 110 has a cam support shaftportion 116 in the form of a cylindrical shape and projected from theintermediate inner bottom wall portion 117 in coaxial relationship withthe guide center axis 110 c. The fixed cam 140 and the lock releasingcam 160 are guided by the cam support shaft portion 116 and disposed inand supported by the fixed case 110 to be rotatable with respect to thefixed case 110 and in coaxial relationship with the guide center axis110 c. The guide shaft 180 is coaxially received in the cam supportshaft portion 116. The above mentioned cam support shaft portion 116 andthe guide shaft 118 constitutes as a whole a guide axial portion definedin the present invention. The fixed case 110, the push cam 130, thefixed cam 140, and the lock releasing cam 160 may have a properlubricant agent such as grease and the like applied thereon according tothe present invention.

On the other hand, the fixed case 110 is provided at its right end sidein FIG. 6 with a pair of inclined guide portions 115 which have thefixed cam 140 rotated around the guide center axis 110 c in response tothe axial displacement of the fixed cam 140. The inclined guide portions115 are inclined at a predetermined lead angle γ1 with respect to theflat surface perpendicular to the guide center axis 110 c, for example,the end surface 110 e of the fixed case 110 and disposed in 180 degreessymmetrical relationship with each other with respect to the guidecenter axis 110 c. Each of the inclined guide portions 115 is in theform of a helically curved shape around the guide center axis 110 c.Here, the term “lead angle” is intended to mean a helical inclinationcorrespondent to a lead angle (tan⁻¹ (lead(L)/circumference length(πd))) in a gear, and here has a value corresponding to the displacement(advance) of the driven side per the specified operation angle range ofthe movable cam taken on a predetermined unit phantom cylindricalsurface.

The fixed cam 140 has a pair of guide engagement portions 141 projectedradially outwardly and spaced from each other at 180 degrees, and heldin engagement with the pair of inclined guide portions 115. As shown inFIG. 9( a), both side ends of each of the guide engagement portions 141are inclined at an lead angle γ1 with respect to a flat surfaceperpendicular to the guide center axis, for example, the center axis 140c of the guide hole 140 a. The guide engagement portions 141 arerespectively held in engagement with the inclined guide portions 115 atthe points spaced apart at a predetermined distance (radius r0) from theguide center axis 110 c of the fixed case 110.

The fixed cam 140 has a pair of release side cam portions 144 opposingto the respective lock releasing cam 160 and having a pair of facingsurfaces 144 a opposing to the lock releasing cam 160, and a pair ofinclined surfaces 144 b held in engagement with the inclined surfaces163 b of the releasing cam portions 163. The engagement of the releaseside cam portions 144 of the fixed cam 140 and the releasing camportions 163 of the lock releasing cam 160 at the inclined surfaces 144b and 163 b by the rotation of the lock releasing cam 160 enables thefixed cam 140 to be axially displaceable in response to the rotation ofthe lock releasing cam 160. Here, the lead angle between the inclinedsurfaces 144 b and 163 b and the flat surface perpendicular to the guidecenter axis 110 c of the fixed case 110 is set at an angle (gentleinclination angle) smaller than the lead angle γ1.

It is therefore understood that the fixed cam 140 is engaged at itsleading end with the lock releasing cam 160 and displaced along theguide center axis 110 c of the fixed case 110 and rotated around theguide center axis 110 c of the fixed case 110, thereby being moved witha helically twisting motion while being guided by the inclined guideportions 115 when the inclined surfaces 144 b of the release side camportions 144 are respectively engaged with the inclined surfaces 163 bof the releasing cam portions 163 of the lock releasing cam 160.

Further, the fixed cam 140 is shown in FIGS. 9( a) to 9(c) and has apair of urging direction changing cam portions 142 and 143 held inopposing relationship with the rotation cam 150. The urging directionchanging cam portions 142 and 143 are engaged with the rotation cam 150at the points smaller in diameter than the predetermined distance r0from the center axis 140 c of the guide hole 140 a coincident with theguide center axis 110 c. The urging direction changing cam portions 142and 143 are held in engagement with the respective cam portions 153 and154 of the rotation cam 150 on phantom cylindrical surfaces (shown intwo dotted lines in FIG. 9( c)) with the different radii r1 and r2 fromthe center axis 140 c.

As shown in FIGS. 9( b) and 10(a), the urging direction changing outercam portion 142, which serves to change the urging direction radiallyoutwardly i.e., outwardly in a radius direction, has a first inclinedcam surface 142 a inclined to the surface perpendicular to the centeraxis 140 c, a second inclined cam surface 142 c inclined oppositely tothe first inclined cam surface 142 a with respect to the surfaceperpendicular to the center axis 140 c, and a top portion 142 bprojected toward the rotation cam 150 between the first inclined camsurface 142 a and the second inclined cam surface 142 c. As shown inFIG. 10( b), the urging direction changing inner cam portion 143, whichserves to change the urging direction radially inwardly i.e., inwardlyin a radius direction, is angularly displaced at 180 degrees withrespect to the urging direction changing outer cam portion 142 whichserves to change the urging direction radially outwardly i.e., outwardlyin a radius direction as mentioned above, and has a first inclined camsurface 143 a inclined to the surface perpendicular to the center axis140 c, a second inclined cam surface 143 c inclined oppositely to thefirst inclined cam surface 143 a with respect to the surfaceperpendicular to the center axis 140 c, and a top portion 143 bprojected toward the rotation cam 150 between the first inclined camsurface 143 a and the second inclined cam surface 143 c. The urgingdirection changing inner cam portion 143 has, below the second inclinedcam surface 143 c, an intermediate speed reduction area 143 d on thesurface perpendicular to the center axis 140 c and is formed with anextended inclined surface 143 e sharply inclined in a direction the sameas the second inclined cam surface 143 c. Here, the intermediate speedreduction areas 142 d, 143 d respectively intervene between the firstinclined cam surfaces 142 a, 143 a and the elongated inclined surfaces142 c, 143 c.

Here, the urging direction changing cam portion 142, 143 of the fixedcam 140 are positioned in opposing relationship with each other acrossthe rotation center axis 140 c of the fixed cam 140 and 180 degreesspaced apart from each other in the rotation direction. The radii r1 andr2 of the urging direction changing cam portions 142, 143 arerespectively larger than predetermined radii. The ratio of the radii r2and r1 is larger than a predetermined ratio, and smaller than a numeral“1”.

On the other hand, the urging direction changing radially-outward camportion 153 of the rotation cam 150 is shown in FIGS. 11( a) to 11(c) tohave a first inclined cam surface 153 a inclined at an inclination anglewith respect to a flat surface perpendicular to the center axis 150 c ofthe guide hole 150 a, a second inclined cam surface 153 c oppositelyinclined with respect to a flat surface perpendicular to the center axis150 c of the guide hole 150 a, and a top portion 153 b projected towardthe fixed cam 140 between the first inclined cam surface 153 a and thesecond inclined cam surface 153 c. As shown in FIGS. 11( a) and 11(b),the urging direction changing radially-inward cam portion 154 of therotation cam 150 is in diametrically opposed relationship with theurging direction changing radially-outward cam portion 153, and close tothe center axis 150 c of the guide hole 150 a in comparison with theurging direction changing radially-outward cam portion 153. In a similarway, the urging direction changing radially-inward cam portion 154 has afirst inclined cam surface 154 a inclined at an inclination angle withrespect to a flat surface perpendicular to the center axis 150 c of theguide hole 150 a, a second inclined cam surface 154 c inclinedoppositely to the first inclined cam surface 154 a with respect to aflat surface perpendicular to the center axis 150 c of the guide hole150 a, and a top portion 154 b projected toward the fixed cam 140between the first inclined cam surface 153 a and the second inclined camsurface 153 c. The radially-inward cam portion 154 has, below the secondinclined cam surface 154 c, an intermediate speed reduction area 154 don the surface perpendicular to the center axis 150 c and is formed withan extended inclined surface 154 e sharply inclined in a direction thesame as the second inclined cam surface 154 c and finally connected tothe fan-shaped hole portion 150 h.

The rotation cam 150 has at its center portion a boss portion 151 inopposing relationship to the cam support shaft portion 116 of the fixedcase 110, the boss portion 151 having at its forward end a pair ofconvex end surface positioning cam portions 151 a to be engaged with thepair of concave end surface positioning cam portions 116 a (see FIGS. 6and 7) provided at the cam support shaft portion 116 of the fixed case110. The rotation cam 150 and the fixed case 110 have end surfacepositioning cam portions 116 a and 151 a, respectively, opposing to eachother along the guide center axis of the fixed case 110. Under the statethat the movable housing 30 is positioned at the neighborhood of itsopened position where the movable housing 30 is mostly spaced apart fromthe fixed housing 20, the rotation cam 150 is disengaged and moved awayfrom the fixed cam 140 while the end surface positioning cam portions116 a and 151 a are engaged with each other so that the movable housing30 is positioned and retained at the opened position.

As shown in FIG. 11( b), the end surface positioning cam portions 116 aand 151 a of the fixed case 110 and the rotation cam 150 are engaged anddisengaged from each other at their radius positions nearer to the guidecenter axis 110 c of the fixed case 110 than the urging directionchanging cam portions 142, 153 and 143, 154 respectively constitutingend cam portions of the fixed cam 140 and rotation cam 150. The engagedportions of the end surface positioning cam portions 116 a and 151 a ofthe fixed case 110 and the rotation cam 150 are set at a predeterminedangle to be imparted disengagement torque when the fixed housing 20 andthe movable housing 30 are manually operated to be opened.

On the other hand, FIG. 4 shows a compression spring 170 providedbetween the rotation cam 150 and the movable case 120 to urge therotation cam 150 toward the fixed cam 140. This means that thecompression spring 170 serves as urging means to urge the rotation cam150 toward the fixed cam 140 in one of the opening operation direction10 c (see FIG. 1) to have the movable case 120 and the movable housing30 moved away from the fixed housing 20 and the closing operationdirection 10 d (see FIG. 1) to have the movable case 120 and the movablehousing 30 moved toward the fixed housing 20 in response to theengagement state of the fixed cam 140 and the rotation cam 150.

For example, under the state that the fixed cam 140 is returned to itsoperation starting position, the movable housing 30 is manually operatedto be positioned in the neighborhood of the closing operation positionhaving the movable housing 30 moved to a position nearest to the fixedhousing 20. At this time, the rotation cam 150 is imparted an axiallyoutward urging force (see an arrow mark 10 c in FIG. 4) by thecompression spring 170 and engaged with the first inclined cam surfaces142 a and 143 a so that the movable housing 30 is urged toward theclosing operation. When the movable housing 30 is operated to theposition where the movable housing 30 is opened more than apredetermined angle with respect to the fixed housing 20, the rotationcam 150 is imparted an axially outward urging force by the compressionspring 170 and engaged with the second inclined cam surfaces 142 c and143 c so that the movable housing 30 is urged toward the openingoperation to have the rotation cam 150 urged toward the openingoperation of the movable housing 30. In this sense, the term “inresponse to the engagement state of the fixed cam 140 and the rotationcam 150” means “in response to anyone of the inclined surfaces of thepair of the urging force changing outer cam portions 142 and 143 of thefixed cam 140 engaged with the fixed cam 150”.

The lead angle γ2 formed between the first inclined cam surfaces 142 aand 143 a of the pair of urging force changing outer cam portions 142and 143 and the surface perpendicular to the guide center axis 110 c ofthe fixed case 110 is lower than the lead angle γ1 formed between theinclined guide portions 115 of the fixed case 110 and the surfaceperpendicular to the guide center axis 110 c of the fixed case 110. Itwill be understood from the foregoing description that the lead angle isa value obtained in response to the displacement (advance) of a drivenside/cam moved angle (θ)×engagement radius (r). This means that theradially inwardly urging direction changing cam 143 is sharply inclinedper a real sliding distance, the lead angle of the radially inwardlyurging direction changing cam 143 is the same as that of the radiallyoutwardly urging direction changing cam 142.

The rotation cam 150 is shown in FIG. 4 as coaxially supported on thefixed case 110 through the guide shaft 180 to ensure that the rotationcam 150 is axially displaceable with respect to the fixed case 110 alongthe guide center axis 110 c and rotatable around the guide center axis110 c.

The guide shaft 180 is shown in FIG. 4 as having a large diameterportion 182 integrally formed with the guide shaft 180 at an axialposition of the guide shaft 180 spaced apart from one end of the guideshaft 180 to be engageable with the intermediate inner bottom wallportion 117 in opposite relationship with the lock releasing cam 160, another end portion 181 securely connected with a stop ring 201 forexample by the way of a caulking method. The bottom wall portion 121 ofthe movable case 120 is stopped to be removed from the guide shaft 180through a spacer ring 202 which is attached on the guide shaft 180 inthe neighborhood of the stop ring 201 and is large in area than the stopring 201. The large diameter portion 182 has a returning spring 190wound and retained thereon.

The movable case 120 is coaxially supported on the fixed case 110 by theguide shaft 180 while being received in a guide hole (no referencenumeral) formed at the center of the bottom wall portion 121 of thebottomed cylindrical body thereof. The guide hole may be made large inlength by making the guide hole projected inwardly. The movable case 120is shown in FIG. 3 to be integrally engaged with the movable housing 30in the rotation direction by the parallel cut portions 122. The movablecase 120 may be provided with axially projected and grooved portions inplace of the parallel cut portions 122.

The returning spring 190 is constituted by a helical coil springintervening for example between a longitudinally extending groove 119 ofthe fixed case 110 and the lock releasing cam 160 to urge the lockreleasing cam 160 to reduce an engagement area of the lock releasing cam160 and the push cam 130 while the helical coil spring is supported onthe large diameter portion 182 of the guide shaft 180. The urging forceof the returning spring 190 allows the fixed cam 140 to be moved by thecompression spring 170 toward the starting position where the movablehousing 30 is urged toward the closing operation position with respectto the fixed cam 140. The lock releasing cam 160 is returned to thepredetermined operation starting position, and the push cam 130 is alsoreturned to its original position. The push cam 130 may be returned tothe original position together with the push button 25 by otherreturning spring.

As mentioned above in the present embodiment, the fixed cam 140 and therotation cam 150 are respectively provided with the urging directionchanging cam portions 142, 143, 153, and 154 as a plurality of kinds ofend cam portions axially opposing to each other at the different radiir1 and r2 from the guide center axis 110 c of the fixed case 110. Theend cam portions 142, 143, 153, and 154 are respectively constituted byurging direction changing outer cam portions 142 and 153 which arechanged in engagement state while being axially urged with each other bythe compression spring 170 to allow the urging direction toward themovable housing 30 to be changed when the push cam 130 is operated tohave the lock releasing cam 160 rotated from the operation startingposition, and also constituted by urging direction changing inner camportions 143 and 154 which are engaged with each other at their innerpositions radially nearer to the guide center axis 110 c of the fixedcase 110 than the engaged positions of the outer urging directionchanging cams 142 and 153 and are changed in engagement state insynchronism with the inner urging direction changing cams 142 and 153while being axially urged with each other to change the urging directiontoward the movable housing 30 by the compression spring 170 when thepush cam 130 is operated to have the lock releasing cam 160 rotated fromthe operation starting position. The operation of the push cam 130 tocause the lock releasing cam 160 to be rotated from the predeterminedoperation starting position enables the fixed cam 140 to be guide by theinclined guide portions 115 and to be driven to rotate by the drivingforce of the rotation cam 150 so that the fixed cam 140 is changed inthe engagement state with the rotation cam 150 to allow the urgingdirection toward the movable case 120 and the movable housing 30 changedunder the influence of the compression spring 170.

In the mobile phone 10 according to the present embodiment, the pushbutton 25 is externally operated to have the push cam 130 to be axiallymoved and displaced in the predetermined direction so that the movablehousing 30 can be rotated to the opened operation position with respectto the fixed housing 20 through the rotation cam 150 under the influenceof the compression spring 170, and that the movable housing 30 can bemanually operated from the returned operation starting position of thefixed cam 140. The completion of the predetermined operations asmentioned above enables the compression spring and the cam to worktogether until the opening and closing operations are automaticallycarried out.

The operation of the mobile phone according to the first embodiment ofthe present invention will be then described hereinafter.

(Manual Opening and Closing Operation)

The following description is directed to the case that the mobile phone10 is manually opened from a folded state, i.e., a state that theoperation surface 21 of the fixed housing 20 is held in face-to-facerelationship with the display screen 31 of the movable housing 30. Theinitial operation state of the opening/closing hinge unit 100 is shownin FIG. 4. Under this state, states of the principal cams of theopening/closing hinge unit 100 are developed and schematically shown inFIG. 12( a). In FIG. 12, the leftward movement of the rotation cam 150indicates a closing operation of the mobile phone 10, and inversely therightward movement of the rotation cam 150 represents an openingoperation of the mobile phone 10.

Under the initial state as shown in FIG. 12( a), i.e., at the initialstage of manually opening operation, the first inclined cam surfaces 142a and 143 a of the fixed cam 140 returned to the respective initialoperation position and regulated from being rotated by the inclinedguide portions 115 are respectively engaged with the cam portions 153and 154 of the rotation cam 150 to have the movable case 120 retained atthe closing position, i.e., the folded position while receiving theurging force to have the movable case 120 urged in the closing directionof the movable housing 30.

When the movable housing 30 is manually rotated with respect to thefixed housing 20 in the opening operation direction, the rotation cam150 is moved to cause the compression spring 170 to be compressed fromthe original position and to slide over the top portions 142 b and 143 bof the cam portions 142 and 143 of the fixed cam 140 against thecompression force of the compression spring 170 so that the urgingdirection of the compression spring 170 is changed toward the openingoperation. This means that users of the mobile phone 10 feel operationalresistance at the initial operation stage to open the movable housing30, however, feel no operational resistance with the movable housing 30since the movable housing 30 is arbitrarily opened after the movablehousing 30 is opened to some extent of the opening operation.

As the opening operation of the movable housing 30 advances with themovable housing 30 approaching to the predetermined opened position, theend surface positioning cam portion 151 a of the rotation cam 150 isbrought into engagement with the end portion of the cam support shaftportion 116 of the fixed case 110 so that the cam portions 153, 154 ofthe rotation cam 150 regulated from being axially displaced is removedfrom the cam portions 142 and 143 of the fixed cam 140 to slide over thecam of the fixed case 110 as seen in FIG. 12( c).

As the opening operation of the movable housing 30 advances further withthe movable housing 30 reaching the predetermined opened position, theend surface positioning cam portion 151 a is fallen into the end surfacepositioning cam portion 116 a of the cam support shaft portion 116 ofthe fixed case 110 and positioned in the rotation direction so that themovable housing 30 is retained at the predetermined opened position withrespect to the fixed housing 20 as shown in FIG. 12( d). At this time,the rotation cam 150 is imparted an urging force from the compressionspring 170 so that the movable housing 30 can be opened with respect tothe fixed housing 20 when receiving a torque more than a predeterminedtorque level, or otherwise is still maintained closed as long as thepush button 25 to be described in detail hereinafter is not operated.

During the above-mentioned period of time, the fixed cam 140 is neitherrotated nor axially displaced even only one time.

When the movable housing 30 is for example manually rotated with respectto the fixed housing 20 by a torque more than the predetermined torquelevel, the end surface positioning cam portion 151 a of the rotation cam150 is brought out of engagement with the end surface positioning camportion 116 a of the cam support shaft portion 116 of the fixed case110. This results in the fact that the operation resistance abruptlybecomes light for the user and that the rotation cam 150 is returned tothe state shown in FIG. 12( c) from the state shown in FIG. 12( d). Therotation cam 150 is further returned to the state shown in FIG. 12( b)to have the cam portions 152 and 153 of the rotation cam 150respectively engaged with the cam portions 142 and 143 of the fixed cam140.

In the state, the operation resistance is increased as the movablehousing 30 is rotated with respect to the fixed housing 20 in theclosing direction, however, the operation resistance is abruptlydecreased to have the movable housing 30 easily closed due to the factthat the urging direction is returned to the closing operation side whenthe cam portions 152 and 153 of the rotation cam 150 is moved whilesliding over the top portions 142 b and 143 b of the cam portions 142and 143 of the fixed cam 140 on the way to the state shown in FIG. 12(a) from the state shown in FIG. 12( b) of the cam portions 152 and 153of the rotation cam 150. It will be understood from the foregoingdescription that the above operation makes it possible to perform theclosing operation with an excellent operation feeling given to theusers.

(Manual Opening Operation by Push button)

The following description will now be made to the case that the pushbutton 25 is operated with the mobile phone 10 maintained in the foldedstate. Under this state, the initial state of the opening/closing hingeunit 100 is as shown in FIG. 4, and as shown in FIG. 13( a) when thestates of the principal cams is schematically shown. This state in FIG.13( a) is the same as the state in FIG. 12( a). In FIG. 13, therightward movement of the rotation cam 150 indicates a closing operationof the mobile phone 10, and inversely the leftward movement of therotation cam 150 represents an opening operation of the mobile phone 10.

In the initial state as shown in FIG. 13( a), i.e., the time to startoperating the push button 25, the first inclined cam surfaces 142 a and143 a of the fixed cam 140 returned to the operation starting positionand regulated from rotating by the inclined guide portions 115 is heldin engagement with the cam portions 153 and 154 of the rotation cam 150,and the movable case 120 is maintained at the closing position, i.e.,the folded position while being urged in the closing operation directionof the housing 30.

When the push button 25 is then pushed by any one of fingers (forexample thumb) of a single hand holding the fixed housing 20 of themobile phone 10, the push cam 130 is axially moved along the guidecenter axis 110 c to have the lock releasing cam 160 at the returnedposition driven to rotate. When the push button 25 is operated over thepredetermined operation amount, the fixed cam 140 and the lock releasingcam 160 are brought into engagement with each other to make it possiblefor the fixed cam 140 to be fallen into the lock releasing cam 160 asshown in FIG. 14 in which the fixed cam 140 is displaced to the positionshown by solid lines to the initial position shown in phantom lines.

At this time, the fixed cam 140 is rotated around the guide center axis110 c while being guided by the inclined guide portions 115 and axiallydisplaced so that the fixed cam 140 is helically moved with respect tothe first inclined cam surfaces 153 a and 154 a of the cam portions 153and 154 of the rotation cam 150 while receiving the axial urging forceof the compression spring 170 through the rotation cam and concurrentlyreceiving the relatively large rotation torque from the inclined guideportions 115 to have the urging direction changed toward the directionshown in FIGS. 13( b) and 14. The rotation torque (T) is indicated by aproduct (T=F×tanγ×r) of an axial thrust force(pressing force) generatedat the engaged portions of the fixed cam 140 and the rotation cam 150, atangent(tanγ) of the lead angle at the engaged portions of the fixed cam140 and the rotation cam 150, and engagement radii(r).

After the urging direction is changed in the above operation, the camportions 153, 154 of the rotation cam 150 are fallen on the secondinclined cam surfaces 142 c, 143 c of the cam portions 142, 143 of thefixed cam 140, thereby making the movable case 120 and the movablehousing 30 to arbitrarily become into the opened state.

As the movable housing 30 continues to be opened and then approaches tothe predetermined opened position, the end surface positioning camportion 151 a of the rotation cam 150 is brought into engagement withthe end portion of the cam support shaft portion 116 of the fixed case110 so that the cam portions 153, 154 of the rotation cam 150 regulatedfrom being axially displaced is removed from the cam portions 142, 143of the fixed cam 140 to slide over the cam of the fixed case 110 as seenin FIG. 13( c) and FIG. 15.

When the opening operation of the movable housing 30 then advancesfurther with the movable housing 30 reaching the predetermined openedposition, the end surface positioning cam portion 151 a of the rotationcam 150 is fallen into the end surface positioning cam portion 116 a ofthe cam support shaft portion 116 of the fixed case 110 to be positionedin the rotation direction so that the movable housing 30 is maintainedat the predetermined opened state with respect to the fixed housing 20as seen in FIG. 13( d) and FIG. 16.

When, on the other hand, the operation force of the push button 25 isreleased, the returning torque of the returning spring 190 forces thelock releasing cam 160 to return to an initial operation startingposition and forces the push cam 130 to move to an initial position.When the rotation cam 150 is moved to the state as shown in FIG. 13( d),the lock releasing cam 160 is moved to the operation starting positionand the fixed cam 140 is also returned to the operation startingposition due to the fact that the fixed cam 140 is pushed up by thereleasing cam portions 163 of the lock releasing cam 160 with an leadangle smaller than that of the inclined guide portions 115.

It will be understood from the foregoing description that theabove-mentioned returned state triggered by the operation of the pushbutton 25 is the same as the state completed by the manual operation.

This means that the closing operation from the above-mentioned returnedstate is also the same as the state completed by the manual operation.

In the above present embodiment of the present invention, the fixed cam140 and rotation cam 150 are respectively provided with the urgingdirection changing outer cam portions 142, 153 and the urging directionchanging inner cam portions 143, 154 different in engagement radius, theengaging states of the engaging portions of the fixed cam 140 androtation cam 150 being changed in synchronism with each other and theurging direction of the compression spring 170 being also changed, sothat the individual urging direction changing cam portions 142, 143,153, and 154 can be provided with sufficient operation spaces, and theengaging cams can sufficiently secure minimum engagement angle rangeseven with a plural kinds of the urging direction changing cam portions142, 143, 153, and 154 provided in the opening/closing device. Thismakes it possible to lower the surface pressure of the engaged camportions, thereby realizing to mold the fixed cam 140 and rotation cam150 with, for example, materials excellent in moldability (such as forexample molding resin and metal powder). The opening/closing device 100according to the present invention can switch urging directions of thecompression spring 170 without further comprising a cam for switchingurging directions of the compression spring 170, and can be small insize and weight, improved in production cost, and improved in durabilitywith a reduced engaging force. The opening/closing device 100 accordingto the present invention can synchronize an engaging operation of theurging direction changing outer cam portions 142, 153 with an engagingoperation of the urging direction changing inner cam portions 143, 154.This means that the urging direction changing outer cam portions 142,153 and the urging direction changing inner cam portions 143, 154.Flexible location in a rotation direction and in an axis direction ofthe urging direction changing outer cam portions 142, 153 with anengaging operation of the urging direction changing inner cam portions143, 154 greatly expands the possibility of opening/closing device.

In this embodiment, the operation angle ranges of the fixed cam 140 andthe rotation cam 150 are wide in comparison with a pair of camspositioned in opposing relationship with each other across the rotationcenter axis 140 c of the fixed cam 140 and 180 degrees spaced apart fromeach other, and the same in distance from center axis as each other byreason that the urging direction changing outer cam portion 142, 153 andthe urging direction changing inner cam portion 143, 154 of the fixedcam 140 and the rotation cam 150 are positioned in opposing relationshipwith each other across the rotation center axis 140 c of the fixed cam140 and 180 degrees spaced apart from each other in the rotationdirection of the second rotation cam.

Each of the urging direction changing cam portions 142, 143, 153, and154 has a shape which can be molded by a molder or the like to be openedin a direction of its rotation axis by reason that the urging directionchanging outer cam portion 142 and the urging direction changing innercam portion 143 of the fixed cam 140 have a first inclined cam surface142 a, 143 a inclined to a surface perpendicular to the center axis 140c, a second inclined cam surface 142 c, 143 c inclined oppositely to thefirst inclined cam surface 142 a, 143 a with respect to the surfaceperpendicular to the center axis 140 c, and a top portion 142 b, 143 bprojected toward the rotation cam 150 between the first inclined camsurface 142 a, 143 a and the second inclined cam surface 142 c, 143 c,on the other hand, the urging direction changing outer cam portion 153and the urging direction changing inner cam portion 154 of the rotationcam 150 have a first inclined cam surface 153 a, 154 a inclined to asurface perpendicular to the center axis 150 c, a second inclined camsurface 153 c, 154 c inclined oppositely to the first inclined camsurface 153 a, 154 a with respect to the surface perpendicular to thecenter axis 150 c, and a top portion 153 b, 154 b projected toward thefixed cam 140 between the first inclined cam surface 153 a, 154 a andthe second inclined cam surface 153 c, 154 c. Each of the urgingdirection changing cam portions 142, 143, 153, and 154 has a shape whichcan be molded by a molder or the like to be opened in a direction of itsrotation axis by reason that the urging direction changing outer camportion 142 and the urging direction changing inner cam portion 143 ofthe fixed cam 140.

In this embodiment, the guide shaft portion can stabilize the rotationcenters of the lock releasing cam 160 and the fixed cam 140 to ensurethat each rotation cam is kept in good working condition. As a result,the opening/closing device can be simply assembled. A center portion ofeach rotation cam is effectively used as a guide portion by reason thatthe fixed case 110 has a cam support axial portion 116 and is in coaxialrelationship with the cam support axial portion 116, the lock releasingcam 160 and the fixed cam 140 are guided by the cam support axialportion 116 in coaxial relationship with the fixed case 110.

In addition, the compression spring 170 can be accommodated in themovable case 120 mounted on the guide shaft 180, and the essentialelements of the opening/closing device can be mounted on the guide shaft180, thereby making it possible to handle the opening/closing hinge unit100 in a unit and thus easy to handle the opening/closing device.Furthermore, the present embodiment of the present invention enables themovable case 120 to have a function not only to retain the one of thecompression spring 170 but also to axially guide the rotation cam 150,and additionally to be engaged with and rotated in unison with themovable housing 30. It is easy to have the opening/closing hinge unit100 built into the hingedly connected portion 11 of the mobile phone 10.

In addition, the fixed case 110 and the rotation cam 150 respectivelyhave end surface positioning cam portions 116 a, 151 a. The rotation cam150 is disengaged from the fixed case 110 when being rotated nearly tothe opened position. At this time, the end surface positioning camportions 116 a, 151 a of the fixed case 110 and the rotation cam 150 areengaged with each other to have the movable housing 30 retained at theopened position. It is therefore possible to attain a smoothtransferring operation between the engagement and disengagementoperations of the second rotation cam and the movable cam and thepositioning operations of the end surface positioning cam portions.

In this case, the end surface positioning cam portions 116 a, 151 aarranged at the center portion of the opening/closing device make itpossible to have the end surface positioning cam portions 116 a, 151 areliably engaged with the fixed cam 140 by reason that the fixed case110 and the rotation cam 150 have respective end surface positioning camportions 116 a, 151 a axially opposed to each other, the rotation cam150 is disengaged from the fixed cam 140 to have the end surfacepositioning cam portions 116 a, 151 a of the fixed case 110 and therotation cam 150 engaged with each other and to have the second memberpositioned and retained at the opening position when the second memberis moved to the opening position where the second member is remotestfrom the first member. The fixed guide member may have a guide shaftportion. In this case, the end surface positioning cam portion of thefixed guide member can be arranged at an appropriate position of theguide shaft portion. The end surface positioning cam portions arrangedat an appropriate position of the guide shaft portion make it possibleto have the end surface positioning cam portions reliably engaged withthe fixed cam.

The movable housing 30 is rotated with respect to the fixed housing 20in response to an urging force by reason that, when the movable housing30 is rotated in an opening operation direction with respect to thefixed housing 20 in response to an urging force of the compressionspring 170, the opening/closing hinge unit 100 can allow the movablehousing 30 to be rotated at a reduced speed.

On the other hand, the mobile phone 10 exemplified in the aboveembodiment using the opening/closing hinge unit 100 is small in size,light in weight, and at relatively low cost by reason that the fixedhousing 20 and the movable housing 30 hingedly connected with each othercollectively constitute an openable and closable housing of a foldabletype. Moreover, the hinge connection portion is excellent in durabilityand reliability.

Second Embodiment

FIG. 17 is a motion explanation view schematically showing operations ofessential portions forming part of the opening/closing device accordingto the second embodiment of the present invention.

The second embodiment is almost the same in whole construction as thefirst embodiment but differs from the first embodiment in the aspect tothe fact that the urging direction changing cam portions and therotation cams engaged with the urging direction changing cam portionsforming part of the first and second embodiment are different in shapefrom each other. For this reason, the following explanation will now bemade with the same reference numerals as those appearing in FIGS. 1-16about the constituting parts or elements of the second embodiment thesame as those of the first embodiment.

As shown in FIG. 17( a), the second inclined cam surfaces 242 c and 243c (the other of the inclined cam surfaces) of the urging directionchanging cam portions 242 and 243 of the fixed cam 240 in the secondembodiment is different in shape from the second inclined cam surfaces142 c and 143 c of the urging direction changing cam portions 142 and143 of the fixed cam 140 in the first embodiment and thus has neither anintermediate speed reduction area 143 d nor an elongated inclinedsurface 143 c. This means that the second inclined cam surfaces 242 cand 243 c of the urging direction changing cam portions 242 and 243 haveno intermediate parts with small lead angles but have straight orslightly curved inclined surfaces. The cam portions 253 and 254 of therotation cam 250 to be engaged with the urging direction changing camportions 242 and 243 of the fixed cam 240, and the angle and shape ofthe inclined surface to be engaged with the second inclined cam surfaces242 c and 243 c of the urging direction changing cam portions 242 and243 are different from those counter parts forming part of the firstembodiment. Other features of the fixed cam 240 and the rotation cam 250of the second embodiment are entirely the same as those of the fixed cam140 and the rotation cam 150 of the first embodiment.

The second embodiment of the present invention can obtain effects andadvantages the same as those of the first embodiment of the presentinvention.

Third Embodiment

FIG. 18 is a motion explanation view schematically showing operations ofessential portions forming part of the opening/closing device accordingto the third embodiment of the present invention.

The opening/closing device according to the third embodiment is almostthe same in whole construction as the opening/closing device accordingto the first embodiment but differs from the first embodiment in theaspect to the fact that the urging direction changing cam portions andthe rotation cams engaged with the urging direction changing camportions forming part of the first and second embodiment are differentin shape from each other. For this reason, the following explanationwill now be made with the same reference numerals as those appearing inFIGS. 1-16 about the constituting parts or elements of the secondembodiment the same as those of the first embodiment.

As shown in FIG. 18( a), the second inclined cam surfaces 342 c and 343c (the other of the inclined cam surfaces) of the urging directionchanging cam portions 342 and 343 of the fixed cam 340 in the secondembodiment is different in shape from the second inclined cam surfaces142 c and 143 c of the urging direction changing cam portions 142 and143 of the fixed cam 140 extending from the top portions 142 b and 143 bin the first embodiment and have intermediate stop areas 342 d and 343 d(intermediate portions) inclined toward the first inclined cam surfaces342 a and 343 a connected with the elongated inclined surfaces 342 e and343 e to form an inclined surface which is other than the intermediatespeed reduction area 143 d as seen in the first embodiment. The pair ofcam portions 353 and 354 to be engaged with the urging directionchanging cam portions 342 and 343 of the fixed cam 340 and the anglewith the one side inclined surface to be engaged with the secondinclined cam surfaces 342 c and 343 c of the urging direction changingcam portions 342 and 343 are different from those in the first andsecond embodiments. The other construction of the fixed cam 340 and therotation cam 350 of the third embodiment is entirely the same as thefixed cam 140 and the rotation cam 150 of the first embodiment. Theintermediate stop areas 342 d, 343 d and the elongated inclined surfaces342 e, 343 e are necessarily not in a flat shape but may be in a curvedshape. The cam surfaces near the intermediate stop areas 342 d, 343 dmay not be bent but curved.

The third embodiment of the present invention can obtain the same effectas those of the first and second embodiments of the present invention.The urging direction changing cam portions 342 and 343 have respectiveintermediate stop areas 342 d and 343 d somewhat inclined oppositely tothe second inclined cam surfaces 342 c and 343 c and the elongatedinclined surfaces 342 e and 343 e, and have the shape of concave,thereby making it possible to temporarily stop the cam portions 353 and354 at their intermediate portions so that the movable housing 30 istemporarily stopped at the position perpendicular to or slightly openedto the fixed housing 20. This can render the third embodiment versatilein the operation. In this case, the opening operation following thetemporal stop of the movable housing 30 may be manually carried out orperformed by the push button.

Further in the above embodiments, the mobile device is exemplified by amobile phone, but the opening/closing device according to the presentinvention may of course be applied to other devices such as PDA andother mobile devices. For the mobile device having a plurality of hingeconnection portions spaced apart from each other, the hinge connectionportions can be employed in such a manner that a plurality ofopening/closing hinge units are arranged in axial alignment with eachother are independently operated or are separately operated by anoperation linkage to transmit operation forces to the units. In theabove embodiment, the center axes of the opening/closing hinge units arearranged in axial alignment with those of the other opening/closinghinge units, but it may be considered that the center axes of theopening/closing hinge units are arranged in parallel while being offsetfrom each other at offset amounts to allow the output of the movablecase to be transmitted to other parts through proper transmitting toolslike gears.

INDUSTRIAL AVAILABILITY OF THE PRESENT INVENTION

As explained in the foregoing description, the present invention canprovide an opening/closing device small in size, light in weight andsuitable as a mobile device by the reason that the rotation of the firstrotation cam with the operation of the operation cam causes the secondrotation cam guided by the inclined guide portion to be rotated whileaxially moving under the pressing force of the movable cam and thus tobe changed in the engagement state with the movable cam, thereby makingthe urging direction of the second member changed with the urging meansso that there is no need for other cams which cause the urging directionof the urging means to be changed, resulting in reducing the number ofparts and elements to be assembled in the opening/closing device. Thepresent invention is advantageous for the opening/closing device and allof the mobile devices using the same, the opening/closing device beingprovided with a function to open and close, only with a simple operationby the push button and the like, a hinge connection body of a foldabletype having first and second members hingedly connected with each other.

1. A hinge device comprising: a fixed guide member (110) fixed to afirst member (20) to be hingedly connected and having a guide centeraxis (10 a) extending along a center axis of a hinge connection; anoperation cam (130) supported on said fixed guide member to bedisplaceable with respect to said fixed guide member in a predeterminedoperation direction by an external operation force; a first rotation cam(160) rotatably supported on said fixed guide member to be engaged withsaid operation cam and to be rotated with respect to said fixed guidemember around said guide center axis in response to the displacement ofsaid operation cam; a second rotation cam (140; 240; 340) supported onsaid fixed guide member to be displaceable along and rotatable aroundsaid guide cent axis in response to the rotation of said first rotationcam; a movable cam (150; 250; 350) regulated from being rotated aroundsaid guide center axis with respect to a second member (30) hingedlyconnected with said first member, and positioned in face-to-facerelationship with said second rotation cam and displaceable with respectto said fixed guide member along said guide center axis and rotatablearound said guide center axis; urging means (170) for urging saidmovable cam toward said second rotation cam in one of an openingoperation direction (10 e) to have said second member moved away fromsaid first member and a closing operation direction (10 d) to have saidsecond member moved toward said first member in response to theengagement state of said second rotation cam and said movable cam, andreturning means (190) for returning said first rotation cam to apredetermined operation starting position of said operation cam and forreturning said second rotation cam to a predetermined operation startingposition where said second member is urged toward said closing operationdirection by said urging means, said second member being rotated withrespect to said first member toward said opening operation directionthrough said movable cam by the urging force of said urging means whensaid operation cam is displaced in said predetermined operationdirection by said external operation force, wherein said second rotationcam and said movable cam respectively have a plurality of kinds of endcam portions ((142, 153), (143, 154); (242, 253), (243, 254); (342,353), (343, 354)) formed thereon at different radiuses from said guidecenter axis in opposing relationship with each other, said plurality ofkinds of end cam portions including urging direction changing outer camportions ((142, 153); (242, 253); (342, 353)) changed in engagementstate while being axially pressed by said urging means to allow theurging direction of said second member to be changed when said operationcam is operated to cause the first rotation cam to be rotated from thepredetermined operation starting position, and urging direction changinginner cam portions ((143, 154); (243, 254); (343, 354)) engaged witheach other at respective positions closer to said guide center axis thansaid urging direction changing outer cam portions and changed inengagement state in synchronism with said urging direction changingouter cam portions while being axially pressed by said urging means toallow the urging direction of said second member to be changed when saidoperation cam is operated to cause the first rotation cam to be rotatedfrom the predetermined operation starting position.
 2. A hinge device asset forth in claim 1, in which said urging direction changing outer camportion (142; 242; 342) and said urging direction changing inner camportion (143; 243; 343) of said second rotation cam are positioned inopposing relationship with each other across said rotation center axisof said second rotation cam and 180 degrees spaced apart from each otherin the rotation direction of said second rotation cam.
 3. A hinge deviceas set forth in claim 1, in which said urging direction changing outercam portion (142; 242; 342) and said urging direction changing inner camportion (143; 243; 343) of said second rotation cam respectively havefirst inclined cam surfaces ((142 a; 242 a; 342 a) or (143 a; 243 a; 343a)) inclined in predetermined directions with respect to a surfaceperpendicular to said guide center axis to urge said movable cam towardthe closing operation direction of said second member when said secondmember is positioned in the neighborhood of the closing operationposition closest with said first member in the state of said secondrotation cam returned to the predetermined operation starting position,and second inclined cam surfaces (((142 c, 142 d, 142 e); (242 c, 242 d,242 e); (342 c, 342 d, 342 e)) or ((143 c, 143 d, 143 e); (243 c, 243 d,243 e); (343 c, 343 d, 343 e))) inclined with respect to said surfaceperpendicular to said guide center axis, and top portions ((142 b; 242b; 342 b) or (143 b; 243 b; 343 b)) projected toward said movable cambetween said first inclined cam surfaces and said second inclined camsurfaces to allow said urging direction of said second member to bechanged by said urging means.
 4. An opening/closing device as set forthin claim 1, in which said fixed guide member has guide shaft portions(116, 180) in coaxial relationship thereof, said first rotation cam andsaid second rotation cam being guided by said guide shaft portion (116)in coaxial relationship with said fixed guide member.
 5. A hinge deviceas set forth in claim 5, further comprising a bottomed cylindrical body(120) supported on and coaxial with said guide shaft portion andintegrally engaged in rotation direction with said movable cam and saidsecond member, said urging means being constituted by a resilient member(170) positioned between said bottomed cylindrical body and said movablecam.
 6. A hinge device as set forth in claim 1, in which said fixedguide member and said movable cam have respective end surfacepositioning cam portions (116 a, 151 a) axially opposing with eachother, said movable cam being disengaged from said second rotation camto have said end surface positioning cam portions of said fixed guidemember and said movable cam engaged with each other and to have saidsecond member positioned and retained at the opening position when saidsecond member is moved to the opening position where said second memberis remotest from said first member.
 7. A hinge device as set forth inclaim 6, in which said end surface positioning cam portions of saidfixed guide member and said movable cam are engaged with and disengagedfrom each other at a radius position closer to said guide center axisthan said kinds of end cam portions.
 8. A hinge device as set forth inclaim 3, in which said second inclined cam surface ((142 c, 142 d, 142e) or (143 c, 143 d, 143 e)) of said urging direction changing outer camportion (142) and said urging direction changing inner cam portion (143)of said second rotation cam has side portions ((142 c, 142 e) or (143 c,143 e)) inclined at different grades with respect to the surfaceperpendicular to said guide center axis and an intermediate portion (142d or 143 d) intervening between said side portions, said intermediateportion rotate said second member at a reduced speed when said secondmember is rotated with respect to said first member in said openingoperation direction.
 9. A hinge device as set forth in claim 3, in whichsaid second inclined cam surface ((342 c, 342 d, 342 e) or (343 c, 343d, 343 e)) of said urging direction changing outer cam portion (342) andsaid urging direction changing inner cam portion (343) of said secondrotation cam has side portions ((142 c, 142 e) or (143 c, 143 e)) and anintermediate portion (142 d or 143 d) intervening between said sideportions, and being inclined oppositely to and said side portions eachother at different grades with respect to the surface perpendicular tosaid guide center axis to allow said intermediate portions of saidsecond inclined cam surfaces to stop said second member when said secondmember is rotated by the urging force of said urging means with respectto said first member in said opening operation direction.
 10. A mobiledevice using said opening/closing device as set forth in claim 1, saidfirst member 20 and said second member 30 hingedly connected with eachother collectively constitute an openable and closable housing of afoldable type.